Generally equipping a _____manship trait will result in better effect (higher damage for ws, higher healing for heals), and longer duration for buffs (bowmanship for quick stride, swordmanship for sentinel...etc) on skills of its corresponding class, never really compared the difference in CD to see if it's reduced or not.

Do keep in mind that, this only works when you are using skills from another class, being a Marauder and equipping axemanship does not result in higher damage or duration of any Marauder skills as far as I can see.